Device for producing slits, grooves, or the like in the surface of monolithic structures



Jilly l, 1930.

A. c. FISCHER 1,769,631

DEVICE FOR PRODUCING SLITS, GROOVES,- OR THE LIKE IN THE SURFACE OFMONOLITHIC STRUCTURES Filed NOV. 29, 1926 Tax/zen Patented a], i, 1930UNITED STATES PATENT OFFICE ALBERT C. FISCHER, OF CHICAGO, ILLINOIS,lASSIGNOR TO THE PHILIP CAREY MANU- FACTURING- COMPANY, A CORPORATION OFOHIO DEVICE FOR PRODUCING SLITS, GROOVES, OR THE LIKE IN THE SURFACE OFMONO- v LITHIC STRUCTURES Application filed November 29, 1926. SerialNo. 151,415.

My present invention relates in general to laying concrete or the likemonolithlc structures, and has particular reference to a device forproducing a slot or slit, or even a groove, in the surface of suchstructures, primarily for the purpose of developing a hne of weakness soas to control cracks in the structure due to expansion and contraction.

For the purpose of illustrating the sallent [0 features of the inventionI have selected that form of the device peculiarly adaptable for use inproducing these slits or slots in the surface of paving structures, suchfor instance, as concrete streets or highways, or pavlng in general. Inthe accompanying drawing, 1n Wl'llCh the form of the invention abovementioned is illustrated, Figure 1 is a perspective view of one form ofthe device.

Figure 2 is a perspective view of a slightly modified form.

Figure 3 is a perspective view of still another form.

Figure 4 is a view in side elevation illustrating the use of theinvention; and Figure 5 is'a section thru a concrete paving. showing theresults accomplished by the use of the invention.

Referring now to the drawing in detall and calling particular attentionto Figure 5, A represents a concrete highway, street or pavement, and itis a more or lesscomrnon practice to equip such a structure with e therpaving joints to compensate for expanslon and con traction, or else toproduce slots or slits 1n the surface thereof which extend a limitedd1stance in the depth of the concrete and provide a line of weaknessboth transversely and longitudinally of the concrete, so that uponexpansion of the concrete any crack resulting from such conditionwill-follow the line of the slot or slit, for instance as illustrated asat B.

-I'have devised a very simple, practical device for producing theseslots or slits, as shown at B in Figure 5. Accordingly, one form of theinvention consists in mounting a block or other like device 5 upon theedge 6 of a sheet metal strip or the like 7.

With such a device I can very conveniently produce these slots orslits-"by laying the device along the area where a slit should beprovided, and then imposing pressure upon the block 5 so as to press thestrip 7 into the concrete. It, of course, is understood that thisoperatlon is performed while the concrete is in a penetrable, plasticcondition, in other words, before it has set. It mustnt be too soft,however, because when the device is removed the concrete must be atleast firm enough to leave the impression on the strip 7 so as to make aslit, for instance as shown at B in Figure 5.

Since the strip 7 is centered in the block 5, 1. e. to say, mountedintermediate longitudinal edges, the under surface of the block onopposite sides of the strip will offer relatively broad contacting areasfor the surface of the concrete, so as to limit the penetration of thestrip 7, and the area of the block will evenly distribute the pressurenecessary to imbed the strip 7, so that the block is not apt to beimbedded in the concrete even though the concrete happened to becomparatively soft. This principle will be readily appreciated uponreference to Figure 4.

Practically the same arrangement is illustrated in Figure 2, except thatthe attached edge of the strip 7 is made with an enlargement 6*, so thatthe strip becomes practically permanently anchored to the block 5, andthere is no danger of the same pulling away from the block. The strip 7for all practical purposes is in reality a blade, since, while it doesntnecessarily require a slicing or cutting action to properly operate,such an action may be used in special instances by forming the strip 7as a long triangle, and as such it may be drawn thru the concrete tomake the slit. This does not mean that the other forms of the devicecannot be drawn thru the concrete, but by cutting the blade on the slanta more pronounced cutting or slicing effect is realized, which would bemore desirable in pulling the device thru the concrete, as compared tojust laying it upon the surface of the concrete and forcing the bladein.

I claim:

1. In a device of the class described, a triangular, blade like stripadapted to be imbedded in a concrete or the like structure'for producinga slit therein, and an inte a1 block-like headfor manipulating thetriangular, strip-like blade, and in which one edge 5 of the triangular,strip-like blade is imbedded, the strip being imbedded in the undersideof the block-like head intermediate the longitudinal edges thereof so asto leave a relatively wide surface on the underside of the block forlimiting the penetration of the triangular, strip-like bladesubstantial- 1y as/and for the purpose described,

2. In a device of the class described, a blade adapted to be imbedded ina concrete struc- 5 ture for producing a slit therein, and a single ieceblade mani ulatin block, said'blade aving one edge t ereof msertablmounted within the block and positione centrally with resgecttllfirfito, and liavin a W031; en};

gaginge gew 'c is angu ar ispose wit respect to the side of the bloc towhich said blade is secured, the angular arrangement of the work enaging edge rendering the device longitudinafiy movable to form a slit inthe concrete structure.

i 3. In a device for marking joints in concrete paving, a blade havingan enlarged head along one edge, and a blade holding block having alongitudinal recess in which the en'- larged head of the blade isadapted to be inserted.

4. In a device for marking joints in concrete paving, a blade having oneedge retroverted to form a bead, and a blade holdin 3 block having alongitudinal recess in whic the beaded edge of the blade is adapted tobe inserted.

Signed at Chicago, Illinois, this 2 1 day of November 1926. ALBERT G.FISCHER.

